Equine Fact or Fiction?

So…true or false?

I thought this week I would blog about some common misconceptions and interesting facts about veterinary care of horses and horse-keeping in general. There is a lot of information available on the internet and from other horse-people, but not all of it is true. It never hurts to ask your veterinarian if you are not sure about a topic; no question is too silly to ask us!

Have you heard that unsoaked beet pulp fed to horses will cause their stomach to explode?

FALSE

This one is my favorite. This is a kind of urban myth set in the country. It is safe to feed dry beet pulp to horses; I have personally done it and my horses are still alive. While it is a good way to add water to a horse's diet, soaking is not necessary, and some horses prefer it dry. In fact, many pelleted feeds sold commercially are beet pulp based, and are fed to horses dry! In horses that tend to bolt their food, any feed eaten too fast may lead to choke, and the particle size of shredded beet pulp may contribute to choking in those horses whether soaked or dry, but there is no scientific proof that stomach rupture is a sequel to consuming it dry. The average horse's stomach has a capacity of 2 to 4 gallons and empties in about 15 minutes. It would be difficult to completely fill that stomach in one meal, and dry beet pulp takes more than 15 minutes to fully expand, even in gastric juices, so the chance for rupture caused by beet pulp is very low.

Horses do not have collarbones (clavicles).

TRUE

This is funny because falling off horses seems to be a common cause of human clavicle fractures! Horses don't need clavicles due to the way they move and bear weight on their forelegs. Their shoulders are attached to the rest of their body by a sling of muscles.

Horses that don't leave home don't need to be vaccinated.

FALSE

I hear this a lot… Most of the diseases we vaccinate horses for are caused by environmental agents, not other horses. The particular vaccines we give and the frequency at which we give them may change with the geographical location of the horse, the amount of travel and contact with other horses, but most of the vaccines stay the same. Rabies, tetanus, west nile virus, botulism, eastern and western encephalomyelitis and Potomac horse fever can all be contracted by horses living alone at home. Strangles, rhinopneumonitis (EHV) and influenza are spread by contact with other horses, either directly or by coming in contact with secretions from infected horses from our hands and shared tools. Horses that do not leave home may not need vaccination for diseases spread horse to horse, but it is best to discuss your horse's individual situation with your veterinarian in order to formulate a plan.

Horses cannot vomit voluntarily.

TRUE

I say voluntarily, because in horses that have either a gastrointestinal blockage or gut motility problem such as enteritis, fluid can back up into the stomach to the point that it sometimes spontaneously exits into the esophagus and comes out the horse's nose. There has to be quite a lot of pressure buildup for this to happen, and the non-vomiting contributes to the pressure. A “vomiting” horse is a very sick horse and needs to be seen by a veterinarian immediately. Horses cannot normally vomit for two reasons. The first is that the muscular ring (the cardiac sphincter) at the top of the stomach in the horse is extremely strong and usually only allows food to move in one direction. The second reason is that the soft palate in the horse is very long and its orientation prevents stomach contents from exiting via the mouth. This is why any expelled fluid comes out through the nose and also why horses cannot breathe well through their mouths.

Horses can get sunburn.

TRUE

Horses with pink colored areas of skin often sunburn in the summer. Many horses have pink skin only under white markings such as a stocking or a snip, but other horses with light hair can have pink skin over their entire bodies. The most common area to suffer from sunburn is the nose, and this can be prevented by applying sunscreen, either one made specifically for horses, a human formulation, or a flyspray containing sunscreen. Some flymasks also have longer nose coverage to help deflect the sun. Horses with less pigment in their skin are also more prone to certain cancers such as squamous cell carcinoma, especially around their eyes. Photosensitivity can also cause skin redness that looks like typical sunburn, but the primary cause is toxicity from certain weeds, chemicals or organ dysfunction. A veterinarian can help determine if one of them is the cause of your horse's skin irritation.

You should put all horse medications in the refrigerator.

FALSE

I'm not sure where the compulsion to refrigerate everything started, but most equine medicines should be kept at room temperature. If you are not sure at what temperature to keep a particular medication, check the label. Most preparations will list a range of optimal temperatures for storage, or at least say “keep at room temperature”, which is usually between 68 and 77 degrees Fahrenheit. Room temperature does not include going in the fridge, freezing out in the barn, or roasting in the hot sun in the car. Common exceptions to the room temperature rule include penicillin G (PPG), reconstituted potassium penicillin (K Pen) or Naxcel (ceftiofur), vaccines, injectable phenylbutazone, and some compounded medications. Those should all stay in the fridge. Keeping a drug at the incorrect temperature could lead to changes in chemical structure, causing loss of efficacy or worse.

Horses that are colicking should be walked so they don't roll.

FALSE

This is a trick question! I'm guessing it is false for the reason you have heard it is true. Many people think that allowing a colicky horse to roll will cause the colon to twist, and therefore the horse should be walked and not allowed to lie down. However, this is not true. Horses roll on a regular basis and very rarely do they cause themselves intestinal harm by doing so. The real reason for walking a colicky horse, aside from helping promote gut motility, is to keep them from going down and injuring themselves externally while rolling or thrashing. Horses that roll from colic pain routinely hit their head or legs on walls or fences. This is a question of which came first, the chicken or the egg. In retrospect, sure, the horse that turned out to need colic surgery had been rolling, but in reality, the horse was rolling because it was in such extreme pain from the previously twisted gut! I usually advise walking a colicky horse for 10 to 15 minutes every few hours. Too much walking exhausts an already tired, painful horse, and its owner too. Letting a horse lie down quietly is okay too. There is no need to make them get up immediately if they need to rest for a while.

Peroxide is good for cleaning wounds.

FALSE

This is one of my biggest pet peeves. I only use peroxide for a handful of things in veterinary work. One is removing blood from white hair near wounds where it has made a drippy mess. Another is flushing out grossly contaminated wounds, such as those filled with grit or fly larvae (yuck). I have also used it to induce vomiting in dogs that have eaten grapes and chocolate. Otherwise I hate peroxide. The foaming and the accompanying stinging give you the impression that it is doing wonders to kill any bacteria and make a healthy wound. However, peroxide is cytotoxic, meaning it is toxic to cells. That means all cells, not just the bad ones. It can also delay healing and has questionable bacterial-killing ability. If you want to clean a wound, first do minimal harm. Without veterinary supervision, sterile saline would be the least toxic thing to use if you have it. I usually suggest using Betadine (iodine) solution diluted with water to a weak tea color, as most people have it at home. Straight Betadine can be irritating and damaging to the skin and needs to be rinsed off. Diluted chlorhexidine solution is also great, but is not readily available in most people's homes.

Feeding bran mash reduces the chances of a horse colicking.

FALSE

One last myth for the day. It makes me kind of sad to say it, because feeding a steaming tub of mash seems to make so many people feel warm and fuzzy, and I feel guilty bursting their bubble! For years it was thought that feeding bran mash would increase the fluid content of ingesta and therefore promote gut motility, decreasing colic episodes. The hydration was supposed to have a laxative effect on the horse. However, recent studies have proven that it does not significantly improve hydration, and the laxative effect is more likely from the upset of normal gut flora caused by the sudden change in diet. This minor laxative effect doesn't have any positive qualities and the change in the normal bacterial composition of the gut can actually predispose to colic. Bran also is high in phosphorus and low in calcium, so feeding a large amount of bran regularly causes mineral imbalances in the diet that can lead to illness. Feeding warm mash on a cold day doesn't have any long-term effects on the energy or core temperature of the horse, either. It probably feels nice and toasty going down and allows the horse to drink water in its food, but the potential negatives outweigh the positives. The research on bran mash suggests that the effect is more about making the horse's owner feel he or she is doing a good thing, unfortunately. A handful of bran a day is not going to cause problems, but there are better ways to add more digestible fiber to the diet.